Physics Our Universe - Gravitation

 PHYSICS – 2

 OUR UNIVERSE – GRAVITATION:

1) Copernican theory is also known as _____________________________ 

Ans : Helio centric theory

2) Mass (M) of earth is   _________

Ans: 6 x 1024   Kg

3) Radius ® of earth is ______________

Ans:  6.4 x 106  m

4) the value of ‘g’ on the earth in S.I. system is _____________

Ans : 9.8 m/s2

5) The value of ‘g’ on the moon is  ____________

Ans : 1.67 m/s 2

6) the value of ‘g’ on the sun is ______________

Ans : 27.4 m/s2

7) The force that keeps the planets in their orbits is the _______ of the sun

Ans : gravitational force

8) The moon makes one revolution about the earth in ______ days

Ans : 27.3

9) The distance of the moon from the earth is about ___________ KMs

Ans: 3.85 x 105

 

10) The basis of Newton’s Laws of universal gravitation is ___________

Ans : Kepler’s Laws

11) Orbiting around the sun in circular orbits is first proposed by _______

Ans : Copernicus

12) The path of a planet around the sun is ________ 

Ans : elliptical

13) The value of ‘g’ at the poles of the earth is _______

Ans : maximum

14) The value of ‘g’ at the equator is __________

Ans : minimum

15) 1 Kilogram weight weight on earth is equal to _________

Ans : 9.8 Newtons

16) The orbital velocity required for an object to go round the earth is _______

Ans : around 8 km/sec

17) Escape velocity of an object, to go out of the gravitational pull of the earth is _____

Ans : 11.2 Km/sec

18) Ecape velocity of an object, to go out of the gravitational pull of the sun is ________

Ans : about 42 KM/sec

19) Mass of a body anywhere in the world is __________

Ans : same

DYNAMICS:

1) Circular motion is a special case of ______

Ans : rotator motion

2) If the string of whirling stone is cut, the stone moves in ___________

Ans: tangential

3) In a uniform circular motion the angular velocity is __________

Ans : constant

4) Centre seeking force is called as ______________

Ans : Centripetal force

5) Centrifugal force means __________

Ans : centre fleeing force or a force directed away from the centre

6) Newton’s laws are valid in _______ frame of reference.

Ans : inertial

7) The study of motion of a body under the action of force is called __________

Ans : dynamics

8) Examples for translator motion ______________

Ans (1)  motionof a flywheel,(2)  motion of earth about  its axis

9) Examples for oscillatory motion ______________

Ans : (1) motion of a pendulum

          (2) motion of mass attached to a string

10) Earth goes round the sun because of _______ of attraction between them.

Ans : gravitational force

11) The gravitational force of attraction provides the necessary ______ for a satellite revolving round a planet.

Ans : centripetal force

12) When electron revolves round the nucleus in an atom, the centripetal force is provided by the _________ of attraction between them.

Ans : electro static force

13) Centrifugal force is also known as ____________

Ans : fictitious force or pseudo force

14)  A _______________ is used to separate particles of higher mass from the lower mass in a given mixture.

Ans : centrifuge

15) When a running car takes a sudden left turn, a man sitting in the back seat falls to the right due to _______ of direction.

Ans : inertia

16) The magnitude of centripetal force and centrifugal force is ______

Ans: same

17) ________ depends on the expected speed of vehicle and the radius of the curvature of the road.

Ans: Banking angle 

18) _______ is a body orbiting around another body.

Ans : Satellite

19) Earth goes round the sun because of ________

Ans : gravitational force of attraction

20) The domestic  churner works on the principle of a __________

Ans : centrifuge

21) The natural satellite of earth is ________

Ans : Moon

22) Satellites and space stations used for study of planets, stars and _____ in the universe.

Ans : galaxies

23) “The orbinal velocity of an artificial satellite is ________ km/sec.

Ans : about 8 and less than 11

24) ____________ force is a pull on the body towards the centre of a circle.

Ans : Centripetal

25) The principle of launching an artificial satellite into orbit is to sufficient intial _____ speed such that it revolves round the earth at the choosen height.

Ans : horizontal

26) The device used to separate particles of higher mass from those of lower mass in a given mixture _______

Ans : centrifuge

27) A car moves on a curved but level road.   The necessary centripetal force on the car is provided by ___________

Ans : friction between the tyres and the road

SIMPLE HARMONIC MOTION : 

1) Any motion that repeats itself along the same path in equal intervals of time is called a _________

Ans : periodic motion

2) Periodic motion is also called as _______

Ans : harmonic  motion

3) A _____________ is associated with every wave motion.

Ans : simple harmonic motion

4) The time period of a simple pendulum is ____________

Ans : directly proportional to the square root of length

ELECTROMAGNETIC SPECTRUM : 

1)What is Spectrum ?

  Ans : Spectrum  is a  group of wave lengths or frequencies.

2)  When a ray of sun light falls on a prism, the transmitted light produces a sequence of colours called a _________

Ans : visible spectrum or VIBGYOR

3) The prisms made of ______ are used to defect Infra red radiations.

Ans : rock salt

4) The invisible radiation before violet are called _______

Ultraviolet radiations

5) __________ radiations are characterized by oscillating electric and magnetic fields perpendicular to each other and perpendicular to the direction of propagation.

Ans : electromagnetic

6) The waves travelling with velocity of light and consisting of Oscillating electric and magnetic fields perpendicular to each other and also perpendicular to the direction of their propagation form the __________

Ans : electromagnetic spectrum

7) The wavelength of the Visible spectrum extends from about 0.4 µ m to _______ that is from violet to red colour.

Ans : 0.7 µ m 

8) _______________ spectrum is emitted when the excited valence electrons in atoms jump to their normal states.

Ans : Visible

9) _____________ radiations are emitted by atoms or molecules when they change their states of rotational to vibrational motion.

Ans : Infra red

10) _______ radiations can be detected by thermopile

Ans : Infra red

11) Infra red radiations find applications in _________

Ans : physiotherapy

12) Infra red radiations are also used to take photographs of objects in ________

Ans : darkness

13) The wave length of the micro waves are in the range from _________ to ________

Ans: 10 µ m to 1 n m

14) Radio waves have  wavelengths from _______ to about _________

Ans : 1 m   ,    100 KM

15) Radio waves are produced by the electromagnetic oscillators of __________

Ans : low frequency

16) _________ radiations are produced by the high energy transitions of the electrons in atoms

Ans : Ultra violet

17) We are protected from ultraviolet radiations of the sun due to _____ layer in our atmosphere.

Ans: ozone

18) Wave lengths of x-rays range from ______ to  ______

Ans : 0.001  nm,  10nm  or 0.01 Å  m 100 Å

19) ___________ are produced in discrete wavelengths in individual transitions amon g the inner electrons of an atom.

Ans : X-rays

20) X-rays of short wavelengths are also called as __________

Ans : hard x-rays

21) Soft  x-rays are used in medical diagnosis called _____________ 

Ans : radiography

22) x-rays are also used to cure some diseases.  This method is called ________

Ans : radio therapy

23) gamma  ( γ ) rays are emitted in __________

Ans : radio activity

24) All electromagnetic waves are ____________ in nature .

Ans : transverse

25) The visible spectrum is emitted when excited valence ____ in atoms jump to their normal states.

Ans: electrons

26) The colour of light emitted by a particular substance is characteristic of the ____ of the substance.

Ans : atoms

27) The light emitted from the sun and distant stars give information about the _____ of the matter present in them.

Ans : composition

28) IR means_______

Ans : Infra red

29) Infra red radiations are emitted by _______ when they change their states of rotational or vibrational motion.

Ans : molecules

30) Hot bodies form sources of the _______ radiations

Ans : Infra red

31) IR radiations can be detected by ___________

Ans : Thermopile or bolomometer

32) Microwaves are produced by high frequency electromagnetic _____ in electric circuits

Ans : Oscillators

33) ___________ waves are used in satellite communications

Ans : Micro waves

34) Mapping of the radio emissions from extra terrestrial sources is known as ________

Ans : radio radiations

35) UV means _______

Ans : Ultra violet rays/ ultra violet spectrum

36) RADAR means _________

Ans : Radio detection and ranging 

37)  The reason of depletion of ozone layer in atmosphere is due to the reactions with ________

Ans: chloro fluro carbons

38) Speed of light in vacuum is ___________

Ans :  3 x 10 8  m/sec

39) Microwaves are often used in _________

Ans : RADAR

40) The type of radiations used in Radar are ________

Ans : Microwaves

SOUND :

1) Speed of sound in air is ________

Ans : 333 mps ( in normal conditions)

2)  _____________ is the phenomenon in which if one  of the two bodies of the same natural frequency is set into vibration, the other body also vibrates with large amplitude under the influence of the first body.

Ans : Resonance

3) ____________ is not transmitted in stationary waves.

Ans : Energy

4) Sound waves travel in air are ___________ waves

Ans : longitudinal

5) _____________ waves are formed in a resonating air column.

Ans: Stationary

6) The periodic vibrations of decreasing amplitude are called ______ vibrations.

Ans : damped

7) Everybody has its own frequency called ________

Ans : natural frequency

8) Velocity of sound is maximum in ______

Ans : solids ( like iron rods)

9) The velocity of sound in vacuum is ________

Ans : zero

10) When the soldiers cross a suspension bridge they are asked to break their steps to prevent_______

Ans : resonance

11) A tuning fork vibrates when a vibrating tuning fork is brought near it.  This is due to _____

Ans : rersonance

12) Velocity of sound on moon is _______

Ans : zero

13) The longest wave is ________

Ans : Radio wave

14) In a resonating air column ____ waves are formed.

Ans : stationary

LIGHT

NATURE OF LIGHT & SOURCES OF LIGHT

1) Newton proposed ________ theory of light

Ans : corpuscles

2) Corpuscles are _____ by the reflecting surface

Ans : repelled

3) Corpuscles are ______ by the refracting surface

Ans : attracted

4) Wave theory of light was proposed by __________

Ans : Huygens

5) According to Newton, the  colours of light are due to difference in the ______ of corpuscles.

Ans : different sizes

6) Light rays can be produced from __________ body

Ans : luminous

7) Examples of luminous bodies are _______

Ans: Sun, Stars

8) Maxwell proposed _________ theory of light

Ans : electromagnetic

9) Light consists of radiations called ________

Ans : photons

10) Light waves are ________

Ans : transverse

11) In a ripple tank , crest of the light wave, behaves as _____ lens

Ans : convex

12) In a ripple tank the trough of light wave behaves as ______ lens

Ans : concave

13) In a ripple tank _____ band is formed due to crests

Ans : bright

14) In a ripple tank _____ band is formed due to troughs

Ans : dark 

15) Speed of light in vacuum is  _________

Ans : 3 x 10  8  m/sec

Visual Photometry: 

1) The visual light is an energy on the _______

Ans : flow

2) Example for self luminous body is ________

Ans : Sun

3) Unit of luminous flux is ________

Ans : Lumen

4) Sun light has its maximum radiant energy close to ________

Ans: green light

LASER: 

1)Laser stands for __________ 

Ans : Light Amplification by Stimulated Emission of Radiation 

2) The light used in destroying ICBM  is in itself is __________

Ans : Laser

3) First laser was called _________

Ans : pulsed laser

4) The basic scientific principle behind a laser was put forward by ________

Ans : Dr. Charles

5) ICBM stands for _____

Ans : Inter Continental Ballistic Missile

6) The property coherence in Laser is called ________

Ans : temporal coherence

7) Lack of coherence makes ordinary light an ______

Ans : optical noise

8) Coherence makes a laser light _____

Ans : optical music

9) The important characteristic properties of laser are ________

Ans : 1) coherence  2) directionality

          3) monochromacity and high intensity

10) Example for monochromatic light is _______

Ans : sodium lamp

11) Laser emits light only in one dirction.  This is called _____ of laser light.

Ans: directionality

12) The process of achieving population inversion is called _________

Ans : pumping ( It is a word used in Lasers)

13) The process of electrons being released on their own from the excited states in atoms and emitting incoherent light is called ________

Ans : spontaneous emission

14) _______ are used for bloodless surgery

Ans : Lasers

15) Lasers are used now for __________

Ans : drilling, cutting materials

16) Lasers are used in guided ______ and to deflect enemy target

Ans : missiles

17) Lasers employed in special 3-dimensional photography are called _______

Ans : Holography

18) The development of lasers which helped in establishing a new revolutionary method of communications called __________

Ans : fibre optic communication

19) The spread of wavelength about the maximum intensity is  called ______

Ans : Band width

20) Ruby laser is an example for ______

Ans : solid laser

21) Helium – Neon laser is an example for _______

Ans : gaseous laser

22) The three dimensional photography is called _____

Ans : Holography

23) The process of achieving “population inversion” is called_____

Ans : pumping

24) By ______ large energy can be concentrated into an extremely small band width.

Ans : Monochromacity

25) The light from an ordinary light source spreads out uniformly in all directions and forms ______ wave fronts around it.

Ans : spherical